1. Field of the Invention
The present invention generally relates to a monitor apparatus of a television system. More specifically, the present invention is directed to a monitor apparatus and a video signal processing circuit capable of selecting image quality modes corresponding to brightness of a room where the monitor apparatus is installed, and also to picture sources.
2. Description of the Related Art
Recently, various image medium with high image qualities such as satellite broadcasting and laser disks have been widely utilized. To monitor such high-quality images under better conditions, for instance, balances in brightness of image, a hue or tint thereof, and a shade of color are adjusted in correspondence with install conditions (e.g., brightness of a room) for the monitor apparatus, and wishes of a user, so that the images can be represented under better conditions.
There are some types of monitor apparatuses capable of selectively setting the image quality modes prepared in the image processor by adjusting such brightness and color tint. These monitor apparatuses are equipped with such image quality modes as "standard", "living" and "theater" in order to accept the setting conditions of the monitor apparatuses and wishes of the user.
The "theater" mode corresponds to a mode that is selected when the movies are monitored. In this "theater" mode, such image processing is carried out that the image qualities of the projected image are approximated to those of the movie film. When the "theater" mode is selected, brightness, or luminance of images is controlled to be low by way of such functions as "bright" and "picture", so that images darker and lighter than the normal images, with shape colors and sharp contour can be obtained. Furthermore, in case that such images are observed, users may enjoy pictures such as movie pictures with having feelings that they are actually in a movie theater by darkening illumination of the monitoring room.
When the movie or the like is monitored in the "theater" mode, the user can have the feeling of being at a live performance, e.g., at the movie theater by darkening illumination of the monitoring room. The conventionally utilized functions such as "bright" and "picture" do not own sufficient dynamic ranges of control levels, and therefore have limitations in lowering brightness of images. As a consequence, even when the "theater" mode is selected, if illumination of the monitoring room would be darkened, brightness of the monitored images would be conversely emphasized. Therefore, there is a problem that the above-described image qualities such as the movie film would be lost.